I’ve noticed this phenomenon with cheap drinking glasses where two pieces of glass were fused together. Had some heavy bottomed tumblers where the bottom would just pop off: The entire set offed itself one by one over the course of a few months.

I highly recommend real imperial pint glasses (aka “Harp style” glasses, 20oz.), the ones with the actual seal stamped into the glass in the bottom, not cheapo knockoffs. I bought a dozen of them from a local Irish pub ten years ago for $4 a piece, and I’ve only broken one (dropped onto the granite counter from 24″ up), and we use these all the time. I frequently drop them, and stuff them pretty much anywhere they fit in the dishwasher. They’ve also survived several moves. The fact that they easily hold pretty much any bottle/can of beer is a nice bonus. Oh, and before I had a dishwasher, an added benefit was that I could get my whole hand inside them to wash them well. Just do it.

It’s possible that the bubbles in the glass are responsible for this. Most dishwashers heat the water to a pretty high temperature for best cleaning results and that could have caused the air inside the bubble to expand. While that might not have been enough to crack it in one go, it could have started a crack in the glass, which opened and closed with every washing cycle as the glass was heated and cooled, progressively increasing the crack size until you reached the strength limit of the glass and then…pop. This is mostly speculation, but I notice that the photo shows a round shape in the glass fracture surface (in the floor of the glass, near the inner surface) which could be a bubble and the source of the crack.

I have had the exact same thing happen to 2 heavy bubble glasses in the last 3 days. I returned one set, then bought a different brand at a totally different store and within 24 hours the bottoms exploded off them also. They were sitting on the counter. It seems the minute you get them wet, they do this. Shouldn’t someone look into this as people could sustain injuries here.